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81.
Satoshi Yoshikawa Minoru Ueno Kenjiro Meguro 《Journal of polymer science. Part A, Polymer chemistry》1979,17(8):2491-2497
The monolayer properties of poly(n-stearyl methacrylate), poly(n-lauryl methacrylate), and their mixtures at various ratios of the two polymers have been studied from the measurements of their surface pressure–area isotherms at air–water interface. The monolayer properties of their mixtures have been compared with those of their corresponding copolymers. The results show that the isotherms of the mixed monolayers have two break points at higher pressures than that of poly(n-lauryl methacrylate). This suggests that the mixtures may form more stable films that consist of separate phases of the two homopolymers, although each phase may contain a small amount of the other. The isotherms of the copolymer monolayers indicate a phase transition from liquid condensed to solid film between 50 segment mole % and 70% poly(n-stearyl methacrylate). The monclayer of these copolymers has properties that differ from those of the corresponding mixtures of two pure homopolymers and is more compatible than the mixtures of pure homopolymers. 相似文献
82.
83.
Satoshi Ikeda 《Foundations of Physics》1983,13(6):629-636
Under the assumption that the so-called space-time fluctuationy(x) in a classical sense, attached to each point of the gravitational field at some microscopic stage, is summarized as the metrical fluctuation in the formg λκ (x)=gλκ (x)·exp2σ(y(x)), some new physical aspects induced by the conformal scalarσ(x) (≡σ(y(x))) are found: By introducing the torsionT κ λμ (x) from a general standpoint, the resulting micro-gravitational field is made to have a conformally non-Riemannian structure, where a special form ofT κ λμ (i.e.,T κ λμ =δ κ λ σμ?δ κ μ σλ(σμ=?σ/?x μ)) shows some peculiar features. An averaging process with respect toy is taken into account, by which the spatial structure of the corresponding macro-field is shown, in general, to have a somewhat “non”-Riemannian structure due to the contributions of the torsionT κ λμ . 相似文献
84.
Junpei Naito Yoko Yamamoto Megumi Akagi Satoshi Sekiguchi Masataka Watanabe Nobuyuki Harada 《Monatshefte für Chemie / Chemical Monthly》2005,60(1):411-445
The CD exciton chirality method was applied to various phenylacetylene alcohols to determine their absolute configurations; the long axis polarized –* transition (max=252nm) of the 4-methoxyphenylacetylene chromophore couples with the transition (max=257nm) of the 4-methoxybenzoate group to generate intense exciton split CD Cotton effects, from the signs of which the absolute configurations of phenylacetylene alcohols were unambiguously determined. As an extension of the results, a new methodology for determining the absolute configurations of acetylene alcohols having the HCCCH(OH)-moiety by combination of the Sonogashira reaction and the CD exciton chirality method has been developed and applied. Since the –* transition of acetylene triple bond is located below 180nm, it is difficult to observe ideal bisignate CD Cotton effects due to the exciton coupling between acetylene and benzoate chromophores. To observe the ideal exciton split Cotton effects necessary for the unambiguous determination of absolute configuration, the terminal acetylene group was converted, by the Sonogashira reaction, to the 4-methoxyphenylacetylene moiety, which exhibits an intense –* absorption band polarized along the long axis of the chromophore at 252nm. As a partner of exciton coupling, 4-methoxybenzoate showing a –* band at 257nm was introduced into the alcohol moiety, and the benzoates formed showed intense bisignate CD Cotton effects, from the signs of which the absolute configurations of original acetylene alcohols could be determined in an unambiguous manner. 相似文献
85.
Motokawa R Annaka M Nakahira T Koizumi S 《Colloids and surfaces. B, Biointerfaces》2004,38(3-4):213-219
By employing small-angle neutron scattering (SANS), we investigated the microstructures of, poly(N-isopropylacrylamide) (PNIPA)-block-poly(ethylene glycol) (PEG) (NE) in deuterated water D2O, as related to macroscopic behaviors of fluidity, turbidity and synerisis. SANS revealed following results: (i) microphase separation occurs at around above 17 °C in a temperature range of transparent sol below 30 °C. In the microdomain appeared in the transparent sol state, both block chains of PNIPA and PEG are swollen by water; (ii) for the NE solution of polymer concentration Wp > 3.5% (w/v), corresponding to opaque gel above 30 °C, a percolated structure, i.e., network-like domain is formed by NE as a result of macrophase separation due to dehydration of the PNIPA chains. As the temperature increases toward 40 °C, the network domain is squeezed along a direction parallel to the NE interface, which leads to increase of the interfacial thickness given by swollen PEG chains and to the macroscopic synerisis behavior. 相似文献
86.
87.
88.
Di Li Naoki Ohashi Shunichi Hishita Taras Kolodiazhnyi Hajime Haneda 《Journal of solid state chemistry》2005,178(11):3293-3302
An overall comparative study was carried out on N-doped, F-doped, and N-F-codoped TiO2 powders (NTO, FTO, NFTO) synthesized by spray pyrolysis in order to elucidate the origin of their visible-light-driven photocatalysis. The comparisons in their experimentally obtained characteristics were based on the analysis of XPS, UV-Vis, PL, NH3-TPD and ESR spectra. The comparisons in their theoretically predicted properties were based on the analysis of the calculated electronic structures. As the results, N-doping into TiO2 resulted in not only the improvement in visible-light absorption but also the creation of surface oxygen vacancies. F-doping produced several beneficial effects including the creation of surface oxygen vacancies, the enhancement of surface acidity and the increase of Ti3+ ions. Doped N atoms formed a localized energy state above the valence band of TiO2, whereas doped F atoms themselves had no influence on the band structure. The photocatalytic tests indicated that the NFTO demonstrated the highest visible-light activity for decompositions of both acetaldehyde and trichloroethylene. This high activity was ascribed to a synergetic consequence of several beneficial effects induced by the N-F-codoping. 相似文献
89.
F-doped TiO2 (FTO) powders were synthesized by spray pyrolysis (SP) from an aqueous solution of H2TiF6. The resulting FTO powders possessed spherical particles with a rough surface morphology and a strong surface acidity. The fluorine concentrations in the FTO powders calculated from XPS spectra significantly depended on SP temperature and ranged from 2.76 to 9.40 at.%. The FTO powder prepared at SP temperature of 1173 K demonstrated the highest photocatalytic activity for the decomposition of gas-phase acetaldehyde under both ultraviolet (UV) and visible light (vis) irradiations, and it was higher than that of commercial P 25. This high photocatalytic activity was ascribed to several beneficial effects produced by F-doping: enhancement of surface acidity, creation of oxygen vacancies, and increase of active sites. It was interesting to point out that the vis photocatalytic activity of FTO powders was achieved by the creation of surface oxygen vacancies rather than the improvement of optical absorption property of bulk TiO2 in vis region. 相似文献
90.
Hino S Ichikawa T Ogita N Udagawa M Fujii H 《Chemical communications (Cambridge, England)》2005,(24):3038-3040
The partial pressure of NH3 gas estimated by Raman spectroscopy indicates that approximately 0.1% NH3 inevitably contaminates the H2 desorbed from a hydrogen storage material composed of LiH and LiNH2 at any temperature up to 400 degrees C in a closed system. 相似文献